[PATCH 2/3] KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range()

From: Sean Christopherson
Date: Thu Oct 21 2021 - 21:00:18 EST


Remove an unnecessary remote TLB flush in kvm_zap_gfn_range() now that
said function holds mmu_lock for write for its entire duration. The
flush was added by the now-reverted commit to allow TDP MMU to flush while
holding mmu_lock for read, as the transition from write=>read required
dropping the lock and thus a pending flush needed to be serviced.

Fixes: 5a324c24b638 ("Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock"")
Cc: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Cc: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
Cc: Ben Gardon <bgardon@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f82b192bba0b..e8b8a665e2e9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5700,9 +5700,6 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
end - 1, true, flush);
}
}
- if (flush)
- kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
- gfn_end - gfn_start);
}

if (is_tdp_mmu_enabled(kvm)) {
--
2.33.0.1079.g6e70778dc9-goog